Start in DxD as Motohama: Leveling Up in Another World - Chapter 37: A level (II) beatdown.

When the spiritual barrier that has been intact for a hundred years is shattered by a meteor, spiritual energy that had disappeared starts to return.The mystical realm slowly begins its revival—magic, witchcraft, curses, supernatural lifeforms, strange and mysterious legends, monsters and gods from other worlds…The old world order collapses, yet the new order is mystifying and chaotic.Just before the unprecedented reformation is here, Tang Qi awakens and finds himself hung on the cross, having turned into an inferior demon and in great pain and agony…With his special ability to see through the nature of all things from the mystical realm and a sly and crafty mind, follow Tang Qi as he develops new skills and powers—as well as making new friends and allies—to battle and protect himself from never before seen supernatural threats in an unfamiliar world!

Daytime belongs to the human world, while Deceit Night returns to the netherworld.Since the arrival of the sinister night, demons and evil spirits have brought disaster to humanity, and generations of our ancestors have struggled to survive.This blade of mine can eliminate evil, slay demons, defeat wickedness, exterminate devils, destroy evil!From now on, nighttime shall be like daytime!

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

Evelyn had a normal happy life until the untimely death of her mother. Her loving father soon became an abusive drunk that would constantly beat her and her older brother Mason. After years of abuse one day Evelyn and Mason managed to escape the terror of their father, when Evelyn finally snapped and killed him.Unfortunately, even though they escaped their rotten father, their lives came to a violent and early end at the hands of a cruel fate.However, when Evelyn woke up after dying, she found herself in a dark damp place. And when she broke free from what confines her, she finds herself reborn as an owl.Follow along as Evelyn lives her second life as an owl in a world of magic and mystery, as she aims to rise up and become the strongest. So, no one can ever dictate her fate again.